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Alcoholics’ ‘injured brains’ work harder to complete simple tasks

November 15, 2011

Finger tapping study shows alcoholics may recruit other brain regions

Alcoholic brains can perform a simple finger-tapping exercise as well as their sober counterparts but their brain must work a lot harder to do it, according to a Vanderbilt study released today by the journal, Alcoholism: Clinical & Experimental Research.

Chronic drinking is associated with abnormalities in the structure, metabolism and function of the brain. One of the consequences of these deficits is impairment of motor functioning.

The new study, using functional magnetic resonance imaging (fMRI) during a finger-tapping exercise, found that the frontal lobe and cerebellum activities were less integrated in alcoholic individuals.

“The relationship was weaker in alcoholic people, even a week after they had stopped drinking,” said lead author Baxter Rogers, Ph.D., research assistant professor of Radiology and Radiological Sciences.

Rogers and colleagues used fMRI to examine 10 uncomplicated chronic alcoholic patients after five to seven days of abstinence and once signs of withdrawal were no longer present, as well as 10 matched healthy controls.

Finger tapping recruits portions of both the cerebellum and frontal cortex, Rogers said, and previous research strongly suggested that both are affected in alcoholism, especially the cerebellum.

“We used fMRI because it measures the function of the entire brain painlessly and non-invasively,” Rogers said. “And it can identify specific brain regions that are involved in tasks, and that are affected in disease.”

The study showed that alcoholic patients could produce the same number of finger taps per minute as did the normal controls, but employed different parts of the brain to do it.

“This suggests that alcoholics needed to compensate for their brain injury,” he said. “They may need to expend more effort, or at least a different brain response, to produce a normal outcome on simple tasks because they are unable to utilize the brain regions needed in an integrated fashion.”

Rogers said that while the study was small, it supports other research showing problems in the frontal-cerebellar brain circuits in alcoholic patients. "Its major contribution is related to studying the simple tasks that alcoholics apparently perform quite normally," he said.

“Studies like this allow us to see what changes in brain strategies are employed by alcoholic patients in task performance, something that is not apparent to an examining physician without fMRI. Better understanding how brain circuits of alcoholics are rewired due to their disease may one day lead to new approaches to healing alcoholism and rehabilitation of these brain dysfunctions,” said Peter Martin, M.D., professor of Psychiatry and Pharmacology, senior author of the study